The studies proposed are on the chemical and optical properties of dehydrogenases. Calorimetric and equilibrium measurements of NAD, NADH and trifluorolactate binding to pig heart lactate dehydrogenase and cytoplasmic malate dehydrogenase are intended to define delta G, and delta H, and delta Cp for these processes. The comparison of LDH and MDH is expected to hear upon the specificity of these enzymes and to develop a fuller understanding of the enzymatic mechanism. Fluorescnece is a major tool in biochemistry and for study of dehydrogenases in particular. Steady-state and time-resolved measurements are to be made to define the fluorescence behavior of individual chromophores.